In information storage systems such as disk drives found in personal computers and other data processing devices, a rigid magnetic storage medium, usually in the shape of a disk, is moved relative to a transducer comprising a read/write head which provides for information introduction to and/or retrieval from the magnetic storage medium. In the design of such devices, it is most desirable from a magnetic standpoint to have the read/write head continually touch the surface of the disk during movement to maximize the signal quality, so that the head slides over the disk surface. However, the magnetic benefits of such a design are outweighed by the wear and material interactions caused by such an arrangement, and such interactions lead to poor system reliability and performance. Accordingly, during movement of the disk medium relative to the read/write head, a certain minimal distance is maintained between the head and the disk medium, which is known in the art as the "fly height." Although a certain "fly height" is necessary, there is a continued interest in the development of designs that provide for lower fly heights.
In order to ensure that the read/write head remains separated from the disk surface during operation, air bearing disk drives have been developed in which the read/write heads move over the disk surface on a thin layer of air. Although air bearing devices provide for the necessary separation of the head from the disk surface, the minimal fly height that is achievable with such air bearing configurations is in the range of 2 to 3.mu. inches.
In an effort to provide for even lower fly heights, disk drive configurations comprising liquid bearings on the surface of the disk have been developed. In such disk configurations, the read/write head moves through the liquid bearing present on the surface of the disk. Use of liquid bearings generally allows the read/write head to be positioned closer to the surface of the disk than is achievable with air bearings, with the distance achievable usually being less than 2.mu. inch. Other advantages provided by liquid bearings include high shock and vibration resistance, reduced stiction, improved wear, long life, the opportunity to have a smooth disk surface, and the like.
Despite the potential benefits of liquid bearings in information storage systems, maintenance of the liquid bearing on the surface of the disk can be difficult, particularly for those disk drives which are not kept in a stable position, such as those found in portable or laptop personal computer devices. Thus, typical liquid bearing devices include a means for maintaining a liquid layer on the surface of the disk, such as a nozzle, wick and the like. Although such configurations succeed in maintaining the lubricant layer on the surface of the disk, there are disadvantages associated with the presence of the additional elements required to maintain the liquid bearing. For example, where a transport wick is employed to deposit fluid on the surface of the disk, the wick can create drag on the disk which then must be compensated for in the drive's control electronics and spin motor, which is undesirable. Furthermore, it is difficult to manufacture such devices because of the complexity of the fluid applications means. In addition, for practical purposes such devices are limited to single disk configurations.
Thus, there is interest in the development of new liquid bearing configurations which do not require the presence of a wick or other liquid bearing maintenance means and yet provide for the presence of a stable liquid bearing on the disk surface.
Ideally, such configurations should provide for fly heights of less than 1.mu. inch.